<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
	</head>
	<body>
		<div class="box1">
			<div class="box2"></div>
		</div>
	</body>
</html>
<style type="text/css">
	.box1{
		border: 10px solid;
	}
	.box2{
		width: 200px;
		height: 200px;
		background-color: #bfa;
		float: left;
	}
	.box1::after{
		content: "";
		display: block;
		clear: both;
	}
</style>